fuel in oil

[flyboy]

I have read in other threads about the fuel pump going bad and pumping fuel directly into the crankcase. I have a fuel smell to my oil, plus a fuel leak SOMEWHERE...

I bought a new fuel pump and just pulled the old fuel pump. It seems like the old fuel pump is working properly - that is, it sucks at the intake and blows out the other side. In addition, if I hold my finger over either the inlet or outlet, it seems to hold pressure.

Is there anywhere else that gas can be getting into the oil?

Also, my new fuel pump looks different than the old fuel pump. How can I be sure I have the correct part? I have a 1978 1800 and the new fuel pump is a BCD 2151. Bought it from Vintage Imports and the listed it as a pump for a 1977-78 spider 1800. Still, I want to be sure before installing...

Thanks!

[racydave]

Why do you suspect a fuel leak? If the diaphram in the pump had a small hole, it could actually leak into the eng. Also is possible fuel could leak thru carb, but it would start hard, and smoke.Its concievable that a pump from a diff manafacturer would look different, it physically needs to bolt up and have same throw-pitch as old pump. Easy way to check for gas in oil, pull dipstick and put fire against it, if it flames up, theres definatly gas in it! Also if your tank seems to have pressure in it, and the return was restricted, I could see a poss problem. If there is a device in the return line thats kinda saucer shaped, remove it, causes nothing but problems...

[mdrburchette]

You might have a stuck or sunk float in the carb. How has it been running?

[flyboy]

There is no doubt that I have fuel in the oil. I can smell it. I suspect another fuel leak because last time I parked the car, the leak soaked a piece of cardboard under the car that I put there specifically to check for fuel and oil drips. It was quite a bit of fuel soaking the cardboard.

As far as the carb and how it is running. I haven't driven it much because I have been replacing fuel lines and fixing the firewall to get the clutch cable in the right place. When I did drive it, it seemed to run fine. Didn't seem to smoke, didn't run rough. However, when parked, it leaked a bunch of gas. I also noticed a gas smell in the oil.

Also if your tank seems to have pressure in it, and the return was restricted, I could see a poss problem. If there is a device in the return line thats kinda saucer shaped, remove it, causes nothing but problems...

I do have pressure in the tank. When I take the gas cap off, it blows out. As far as the saucer shaped item, it isn't the pressure regulator that is before the fuel pump inlet that you are referring to is it? Is there another pressure regulator in the return line? I haven't noticed one but haven't looked that carefully. I have not replaced all of the return line fuel lines (at least I don't think I have) so I will give that a shot. I am guessing that the pressure in the tank could cause fuel to leak when the car is parked and practically empty the tank?

It is a wee bit dark here right now so I will have to look at things over the weekend.

[So Cal Mark]

if you're getting that much fuel into the oil, I'd replace the pump. Fuel leaks onto the ground really have nothing to do with fuel in the oil

[danaspider]

I had a problem in the 70's on a 74 spider where the oil was getting diluted with gas after a few hundred miles. This turned out the be a leaky carb gasket. So you might look in that area. As to your leaking fuel on the ground, have you narrowed this down to an area of the car that it is leaking from?

Can always pull the mechanical pump and try an electric pump. Just remember to cover the hole where the old pump was. This might even help your running in hot weather, or starting after the car has been sitting when hot.

[Danno]

I had a problem in the 70's on a 74 spider where the oil was getting diluted with gas after a few hundred miles. This turned out the be a leaky carb gasket.

I never claim to be knowledgeable of this sort of thing, but how in the world does gas get into the oil anywhere near the carb?

[So Cal Mark]

only by severe flooding, filling the cylinders with raw fuel then leaking past the rings

[flyboy]

Thanks everyone for the helpful information. I sure hope the carb isn't flooding the cylinders and leaking past the rings. That sounds nasty!

I did get the fuel pump changed out and it seems to be working well. Of course, in the process, I lost my speedometer (I am hoping I just unplugged the relay by accident while replacing fuel lines) and now I am having a problem with my slow idle - as in it is so slow that it eventually dies. It had been idling well prior to the fuel pump change out. I checked the idle adjust screw, screwed it all the way in, and it didn't have any impact on the idle speed. I'll search the archives for solutions and if I don't find anything I will post a new topic.

one of these days I really will be out on the road!

[So Cal Mark]

if you turned the mixture screw all of the way in, and the car is still idling then you are getting fuel from another source besides the idle circuit. That would explain some of the fuel in the oil condition you have. Is the idle speed under 1000rpm? If it is, then the float could be set too high, or the secondary throttle plate may not be closing completely

[mbouse]

any chance the fuel return line is accidently connected to the intake manifold and vacuum is pulling in fuel from the tank?

[So Cal Mark]

that would be the oddest thing I've ever seen? What would be attached to the return nipple in the carb then?

[flyboy]

if you turned the mixture screw all of the way in, and the car is still idling then you are getting fuel from another source besides the idle circuit. That would explain some of the fuel in the oil condition you have. Is the idle speed under 1000rpm? If it is, then the float could be set too high, or the secondary throttle plate may not be closing completely

OK, I guess I need to be more specific. The screw I turned all the way in is on the throttle linkage at the carb - I have not yet touched the mixture adjusting screw. If I depress the gas pedal a half inch, the car holds fine at low rpm. Hence, I had hoped that adjusting the screw on the throttle linkage would be sufficient to increase the idle speed. It didn't work.

My fast idle is fine but once the fast idle kicks off, the rpms drop to about 300. It holds on there for a while and then eventually dies. Any ideas why this condition would suddenly appear after changing out at fuel pump? As I said, it had previously been idling just fine.

It sounds like my next step is to adjust the mixture control screw. I'll have to read up on this because I don't want to screw up a carb that previously seemed to be working well.

[So Cal Mark]

maybe the fast idle cam wasn't dropping off all the way previously. Even with the speed screw turned all the way in the car won't idle? Are you turning the fast idle screw maybe, and not the throttle stop screw?

[flyboy]

Hmmm. Just looked at the carb manual and it looks like I was adjusting the fast idle screw. No wonder it didn't do anything with the car warmed up. Looks like the throttle stop screw is located on the other side of the carb. Good catch Mark! On other cars I have worked on (which isn't that many), I have always just adjusted the first screw I come to when I follow the throttle cable to the carb or FI.

I'll make the adjustments to both the normal idle and the fast idle tonight according to the carb manual.

Thanks!